Evidence for nutrient enrichment of high-elevation lakes in the Sierra Nevada, California
TLDR
In this paper, longterm measurements (1983•2001) of nutrients and seston in Emerald Lake (Sierra Nevada, California) have revealed ecologically significant patterns, both during spring runoff and during growing seasons, and were likely the result of increased P loading to the lake and the release of phytoplankton from P limitation.Abstract:
Long-term measurements (1983‐2001) of nutrients and seston in Emerald Lake (Sierra Nevada, California) have revealed ecologically significant patterns. Nitrate, both during spring runoff and during growing seasons, declined from 1983 through 1995. Declining snowmelt nitrate was caused primarily by changes in snow regime induced by the 1987‐1992 drought: years with shallow, early melting snowpacks had lower snowmelt nitrate concentrations owing to less labile N production in catchment soils and longer plant growing seasons. However, nitrate declines during growing seasons carried through the wetter years of 1993‐2000 and are likely the result of increased P loading to the lake and the release of phytoplankton from P limitation. Contemporaneous with these changes was an increase in algal biomass and a shift from P limitation toward more frequent N limitation of phytoplankton abundance. Particulate carbon concentrations in the late 1990s were two- to threefold greater than in the early 1980s. These trends were reflected in a larger set of Sierra Nevada lakes sampled as part of synoptic surveys ( n 5 28). Between 1985 and 1999, nitrate decreased and total P increased in .70% of the lakes sampled. Our data suggest that lakes throughout the Sierra Nevada are experiencing measurable eutrophication in response to the atmospheric deposition of nutrients.read more
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Recent advances in the understanding and management of eutrophication
TL;DR: In the years ahead, climate warming will aggravate eutrophication in lakes receiving point sources of nutrients, as a result of increasing water residence times, which will increasingly favor the replacement of diatoms by nitrogen-fixing Cyanobacteria as mentioned in this paper.
Journal ArticleDOI
Ecological Effects of Nitrogen Deposition in the Western United States
Mark E. Fenn,Jill S. Baron,Edith B. Allen,Heather M. Rueth,Koren R. Nydick,Linda H. Geiser,William D. Bowman,James O. Sickman,James O. Sickman,Thomas Meixner,Dale W. Johnson,Peter Neitlich +11 more
TL;DR: In the western United States vast acreages of land are exposed to low levels of atmospheric nitrogen (N) deposition, with interspersed hotspots of elevated N deposition downwind of large, expanding metropolitan centers or large agricultural operations.
Journal ArticleDOI
Increasing Eolian Dust Deposition in the Western United States Linked to Human Activity
Jason C. Neff,Ashley P. Ballantyne,G. L. Farmer,Natalie M. Mahowald,Natalie M. Mahowald,Jessica L. Conroy,Christopher C. Landry,Jonathan T. Overpeck,Thomas H. Painter,Corey R. Lawrence,Richard L. Reynolds +10 more
TL;DR: In this article, the accumulation rates and geochemical properties of alpine lake sediments from the western interior United States for the past 5,000 years have been determined and it was shown that dust load levels increased by 500% above the late Holocene average following the increased western settlement of the United States during the nineteenth century.
Journal ArticleDOI
The Novel and Endemic Pathogen Hypotheses: Competing Explanations for the Origin of Emerging Infectious Diseases of Wildlife
Lara J. Rachowicz,Jean-Marc Hero,Jean-Marc Hero,Ross A. Alford,John W. Taylor,Jess A. T. Morgan,Vance T. Vredenburg,James P. Collins,Cheryl J. Briggs +8 more
TL;DR: Current evidence suggests chytridiomycosis may be a novel pathogen being spread worldwide by carriers; until the authors know how much genetic variation to expect in an endemic strain, however, it cannot yet conclude that B. dendrobatidis is a novel Pathogen.
Book
Freshwater Microbiology: Biodiversity and Dynamic Interactions of Microorganisms in the Aquatic Environment
TL;DR: This work has shown clear trends in Microbial Diversity and Freashwater Ecosystems and in particular the role of Protozoa and Invertebrates in the Freshwater Environment and their role in the Response to Nutrient Levels.
References
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The simultaneous analysis of total nitrogen and total phosphorus in natural waters
TL;DR: In this article, the persulphate oxidation method for the simultaneous determination of total nitrogen and total phosphorus in water has been described and compared with a former method using separate determinations, stability of stored samples and the oxidation reagent, as well as the influence of the time elapsed between sampling and cooking.